THE PRESIDENT'S CONSTITUTIONAL AUTHORITY TO CONDUCT MILITARY OPERATIONS AGAINST TERRORISTS AND NATIONS SUPPORTING THEM

THE PRESIDENT'S CONSTITUTIONAL AUTHORITY TO CONDUCT
MILITARY OPERATIONS AGAINST TERRORISTS AND NATIONS SUPPORTING THEM

The President has broad constitutional power to take military action
in response to the terrorist attacks on the United States on September 11,
2001. Congress has acknowledged this inherent executive power in both the
War Powers Resolution and the Joint Resolution passed by Congress on September
14, 2001.

The President has constitutional power not only to retaliate against
any person, organization, or State suspected of involvement in terrorist attacks
on the United States, but also against foreign States suspected of harboring
or supporting such organizations.

The President may deploy military force preemptively against terrorist
organizations or the States that harbor or support them, whether or not they
can be linked to the specific terrorist incidents of September 11.

September 25, 2001

MEMORANDUM OPINION FOR THE DEPUTY COUNSEL TO THE PRESIDENT

You have asked for our opinion as to the scope of the President's
authority to take military action in response to the terrorist attacks on
the United States on September 11, 2001. We conclude that the President has
broad constitutional power to use military force. Congress has acknowledged
this inherent executive power in both the War Powers Resolution, Pub. L. No.
93-148, 87 Stat. 555 (1973), codified at 50 U.S.C. §§ 1541-1548 (the
"WPR"), and in the Joint Resolution passed by Congress on September 14, 2001,
Pub. L. No. 107-40, 115 Stat. 224 (2001). Further, the President has the constitutional
power not only to retaliate against any person, organization, or State suspected
of involvement in terrorist attacks on the United States, but also against
foreign States suspected of harboring or supporting such organizations. Finally,
the President may deploy military force preemptively against terrorist organizations
or the States that harbor or support them, whether or not they can be linked
to the specific terrorist incidents of September 11.

Our analysis falls into four parts. First, we examine the Constitution's
text and structure. We conclude that the Constitution vests the President
with the plenary authority, as Commander in Chief and the sole organ of the
Nation in its foreign relations, to use military force abroad - especially
in response to grave national emergencies created by sudden, unforeseen attacks
on the people and territory of the United States. Second, we confirm that
conclusion by reviewing the executive and judicial statements and decisions
interpreting the Constitution and the President's powers under it. Third,
we analyze the relevant practice of the United States, including recent history,
that supports the view that the President has the authority to deploy military
force in response to emergency conditions such as those created by the September
11, 2001, terrorist attacks. Finally, we discuss congressional enactments
that, in our view, acknowledge the President's plenary authority to use force
to respond to the terrorist attack on the United States.

Our review establishes that all three branches of the Federal Government
- Congress, the Executive, and the Judiciary - agree that the President has
broad authority to use military force abroad, including the ability to deter
future attacks.

I.

The President's constitutional power to defend the United States and the
lives of its people must be understood in light of the Founders' express intention
to create a federal government "cloathed with all the powers requisite to
[the] complete execution of its trust." The Federalist No. 23, at
122 (Alexander Hamilton) (Charles R. Kesler ed., 1999). Foremost among the
objectives committed to that trust by the Constitution is the security of
the Nation. (1) As Hamilton explained in arguing
for the Constitution's adoption, because "the circumstances which may affect
the public safety are [not] reducible within certain determinate limits, .
. . it must be admitted, as a necessary consequence that there can be no limitation
of that authority which is to provide for the defense and protection of the
community in any matter essential to its efficiency." Id.
(2)

"It is 'obvious and unarguable' that no governmental interest is more compelling
than the security of the Nation." Haig v. Agee, 453 U.S. 280, 307
(1981) (citation omitted). Within the limits that the Constitution itself
imposes, the scope and distribution of the powers to protect national security
must be construed to authorize the most efficacious defense of the Nation
and its interests in accordance "with the realistic purposes of the entire
instrument." Lichter v. United States, 334 U.S. 742, 782 (1948).
Nor is the authority to protect national security limited to actions necessary
for "victories in the field." Application of Yamashita, 327 U.S.
1, 12 (1946). The authority over national security "carries with it the inherent
power to guard against the immediate renewal of the conflict." Id.

We now turn to the more precise question of the President's inherent constitutional
powers to use military force.

Constitutional Text. The text, structure and history of the Constitution
establish that the Founders entrusted the President with the primary responsibility,
and therefore the power, to use military force in situations of emergency.
Article II, Section 2 states that the "President shall be Commander in Chief
of the Army and Navy of the United States, and of the Militia of the several
States, when called into the actual Service of the United States." U.S. Const.
art. II, § 2, cl. 1. He is further vested with all of "the executive Power"
and the duty to execute the laws. U.S. Const. art. II, § 1. These powers give
the President broad constitutional authority to use military force in response
to threats to the national security and foreign policy of the United States.
(3) During the period leading up to the Constitution's ratification,
the power to initiate hostilities and to control the escalation of conflict
had been long understood to rest in the hands of the executive branch.
(4)

By their terms, these provisions vest full control of the military forces
of the United States in the President. The power of the President is at its
zenith under the Constitution when the President is directing military operations
of the armed forces, because the power of Commander in Chief is assigned solely
to the President. It has long been the view of this Office that the Commander-in-Chief
Clause is a substantive grant of authority to the President and that the scope
of the President's authority to commit the armed forces to combat is very
broad. See, e.g., Memorandum for Honorable Charles W. Colson, Special
Counsel to the President, from William H. Rehnquist, Assistant Attorney General,
Office of Legal Counsel, Re: The President and the War Power: South Vietnam
and the Cambodian Sanctuaries (May 22, 1970) (the "Rehnquist Memo").
The President's complete discretion in exercising the Commander-in-Chief power
has also been recognized by the courts. In the Prize Cases, 67 U.S.
(2 Black) 635, 670 (1862), for example, the Court explained that, whether
the President "in fulfilling his duties as Commander in Chief" had met with
a situation justifying treating the southern States as belligerents and instituting
a blockade, was a question "to be decided by him" and which the Court
could not question, but must leave to "the political department of the Government
to which this power was entrusted." (5)

Some commentators have read the constitutional
text differently. They argue that the vesting of the power to declare war gives
Congress the sole authority to decide whether to make war.
(6) This view misreads the constitutional text and misunderstands
the nature of a declaration of war. Declaring war is not tantamount to making
war - indeed, the Constitutional Convention specifically amended the working
draft of the Constitution that had given Congress the power to make war. An
earlier draft of the Constitution had given to Congress the power to "make"
war. When it took up this clause on August 17, 1787, the Convention voted to
change the clause from "make" to "declare." 2 The Records of the Federal
Convention of 1787, at 318-19 (Max Farrand ed., rev. ed. 1966) (1911).
A supporter of the change argued that it would "leav[e] to the Executive the
power to repel sudden attacks." Id. at 318. Further, other
elements of the Constitution describe "engaging" in war, which demonstrates
that the Framers understood making and engaging in war to be broader than simply
"declaring" war. See U.S. Const. art. I, § 10, cl. 3 ("No State
shall, without the Consent of Congress . . . engage in War, unless actually
invaded, or in such imminent Danger as will not admit of delay."). A State constitution
at the time of the ratification included provisions that prohibited the governor
from "making" war without legislative approval, S.C. Const. art. XXVI (1776),
reprinted in 6 The Federal and State Constitutions 3247 (Francis
Newton Thorpe ed., 1909). (7) If the
Framers had wanted to require congressional consent before the initiation of
military hostilities, they knew how to write such provisions.

Finally, the Framing generation well understood that declarations of war
were obsolete. Not all forms of hostilities rose to the level of a declared
war: during the seventeenth and eighteenth centuries, Great Britain and colonial
America waged numerous conflicts against other states without an official
declaration of war. (8) As Alexander
Hamilton observed during the ratification, "the ceremony of a formal denunciation
of war has of late fallen into disuse." The Federalist No. 25, at
133 (Alexander Hamilton). Instead of serving as an authorization to begin
hostilities, a declaration of war was only necessary to "perfect" a conflict
under international law. A declaration served to fully transform the international
legal relationship between two states from one of peace to one of war. See
1 William Blackstone, Commentaries *249-50. Given this context, it
is clear that Congress's power to declare war does not constrain the President's
independent and plenary constitutional authority over the use of military
force.

Constitutional Structure. Our reading of the text is reinforced
by analysis of the constitutional structure. First, it is clear that the Constitution
secures all federal executive power in the President to ensure a unity in
purpose and energy in action. "Decision, activity, secrecy, and dispatch will
generally characterize the proceedings of one man in a much more eminent degree
than the proceedings of any greater number." The Federalist No. 70,
at 392 (Alexander Hamilton). The centralization of authority in the President
alone is particularly crucial in matters of national defense, war, and foreign
policy, where a unitary executive can evaluate threats, consider policy choices,
and mobilize national resources with a speed and energy that is far superior
to any other branch. As Hamilton noted, "Energy in the executive is a leading
character in the definition of good government. It is essential to the protection
of the community against foreign attacks." Id. at 391. This is no
less true in war. "Of all the cares or concerns of government, the direction
of war most peculiarly demands those qualities which distinguish the exercise
of power by a single hand." Id. No. 74, at 415 (Alexander Hamilton).
(9)

Second, the Constitution makes clear that the process used for conducting
military hostilities is different from other government decisionmaking. In
the area of domestic legislation, the Constitution creates a detailed, finely
wrought procedure in which Congress plays the central role. In foreign affairs,
however, the Constitution does not establish a mandatory, detailed, Congress-driven
procedure for taking action. Rather, the Constitution vests the two branches
with different powers - the President as Commander in Chief, Congress with
control over funding and declaring war - without requiring that they follow
a specific process in making war. By establishing this framework, the Framers
expected that the process for warmaking would be far more flexible, and capable
of quicker, more decisive action, than the legislative process. Thus, the
President may use his Commander-in-Chief and executive powers to use military
force to protect the Nation, subject to congressional appropriations and control
over domestic legislation.

Third, the constitutional structure requires that any ambiguities in the
allocation of a power that is executive in nature - such as the power to conduct
military hostilities - must be resolved in favor of the executive branch.
Article II, section 1 provides that "[t]he executive Power shall be vested
in a President of the United States." U.S. Const. art. II, § 1. By contrast,
Article I's Vesting Clause gives Congress only the powers "herein granted."
Id. art. I, § 1. This difference in language indicates that Congress's
legislative powers are limited to the list enumerated in Article I, section
8, while the President's powers include inherent executive powers that are
unenumerated in the Constitution. To be sure, Article II lists specifically
enumerated powers in addition to the Vesting Clause, and some have argued
that this limits the "executive Power" granted in the Vesting Clause to the
powers on that list. But the purpose of the enumeration of executive powers
in Article II was not to define and cabin the grant in the Vesting Clause.
Rather, the Framers unbundled some plenary powers that had traditionally been
regarded as "executive," assigning elements of those powers to Congress in
Article I, while expressly reserving other elements as enumerated executive
powers in Article II. So, for example, the King's traditional power to declare
war was given to Congress under Article I, while the Commander-in-Chief authority
was expressly reserved to the President in Article II. Further, the Framers
altered other plenary powers of the King, such as treaties and appointments,
assigning the Senate a share in them in Article II itself.
(10) Thus, the enumeration in Article II marks the points at which
several traditional executive powers were diluted or reallocated. Any other,
unenumerated executive powers, however, were conveyed to the President by
the Vesting Clause.

There can be little doubt that the decision to deploy military force is
"executive" in nature, and was traditionally so regarded. It calls for action
and energy in execution, rather than the deliberate formulation of rules to
govern the conduct of private individuals. Moreover, the Framers understood
it to be an attribute of the executive. "The direction of war implies the
direction of the common strength," wrote Alexander Hamilton, "and the power
of directing and employing the common strength forms a usual and essential
part in the definition of the executive authority." The Federalist No.
74, at 415 (Alexander Hamilton). As a result, to the extent that the constitutional
text does not explicitly allocate the power to initiate military hostilities
to a particular branch, the Vesting Clause provides that it remain among the
President's unenumerated powers.

Fourth, depriving the President of the power to decide when to use military
force would disrupt the basic constitutional framework of foreign relations.
From the very beginnings of the Republic, the vesting of the executive, Commander-in-Chief,
and treaty powers in the executive branch has been understood to grant the
President plenary control over the conduct of foreign relations. As Secretary
of State Thomas Jefferson observed during the first Washington Administration:
"the constitution has divided the powers of government into three branches
[and] has declared that the executive powers shall be vested in the president,
submitting only special articles of it to a negative by the senate." Due to
this structure, Jefferson continued, "the transaction of business with foreign
nations is executive altogether; it belongs, then, to the head of that department,
except as to such portions of it as are specially submitted to the senate.
Exceptions are to be construed strictly." Thomas Jefferson, Opinion on
the Powers of the Senate (1790), reprinted in 5 The Writings
of Thomas Jefferson, at 161 (Paul L. Ford ed., 1895). In defending President
Washington's authority to issue the Neutrality Proclamation, Alexander Hamilton
came to the same interpretation of the President's foreign affairs powers.
According to Hamilton, Article II "ought . . . to be considered as intended
. . . to specify and regulate the principal articles implied in the definition
of Executive Power; leaving the rest to flow from the general grant of that
power." Alexander Hamilton, Pacificus No. 1 (1793), reprinted
in 15 The Papers of Alexander Hamilton, at 33, 39 (Harold C.
Syrett et al. eds., 1969). As future Chief Justice John Marshall famously
declared a few years later, "The President is the sole organ of the nation
in its external relations, and its sole representative with foreign nations.
. . . The [executive] department . . . is entrusted with the whole foreign
intercourse of the nation . . . ." 10 Annals of Cong.613-14 (1800).
Given the agreement of Jefferson, Hamilton, and Marshall, it has not been
difficult for the executive branch consistently to assert the President's
plenary authority in foreign affairs ever since.

In the relatively few occasions where it has addressed foreign affairs, the
Supreme Court has agreed with the executive branch's consistent interpretation.
Conducting foreign affairs and protecting the national security are, as the
Supreme Court has observed, "'central' Presidential domains." Harlow v.
Fitzgerald, 457 U.S. 800, 812 n.19 (1982). The President's constitutional
primacy flows from both his unique position in the constitutional structure,
and from the specific grants of authority in Article II that make the President
both the Chief Executive of the Nation and the Commander in Chief. See
Nixon v. Fitzgerald, 457 U.S. 731, 749-50 (1982). Due to the President's
constitutionally superior position, the Supreme Court has consistently "recognized
'the generally accepted view that foreign policy [is] the province and responsibility
of the Executive.'" Department of the Navy v. Egan, 484 U.S. 518,
529 (1988) (quoting Haig v. Agee, 453 U.S. at 293-94). "The Founders
in their wisdom made [the President] not only the Commander-in-Chief but also
the guiding organ in the conduct of our foreign affairs," possessing "vast
powers in relation to the outside world." Ludecke v. Watkins, 335
U.S. 160, 173 (1948). This foreign affairs power is exclusive: it is "the
very delicate, plenary and exclusive power of the President as sole organ
of the federal government in the field of international relations - a power
which does not require as a basis for its exercise an act of Congress." United
States v. Curtiss-Wright Export Corp., 299 U.S. 304, 320 (1936).

Conducting military hostilities is a central tool for the exercise of the
President's plenary control over the conduct of foreign policy. There can
be no doubt that the use of force protects the Nation's security and helps
it achieve its foreign policy goals. Construing the Constitution to grant
such power to another branch could prevent the President from exercising his
core constitutional responsibilities in foreign affairs. Even in the cases
in which the Supreme Court has limited executive authority, it has also emphasized
that we should not construe legislative prerogatives to prevent the executive
branch "from accomplishing its constitutionally assigned functions." Nixon
v. Administrator of General Servs., 433 U.S. 425, 443 (1977).

II.

Executive Branch Construction and Practice. The position we take
here has long represented the view of the executive branch and of the Department
of Justice. Attorney General (later Justice) Robert Jackson formulated the
classic statement of the executive branch's understanding of the President's
military powers in 1941:

Article II, section 2, of the Constitution provides that the President "shall
be Commander in Chief of the Army and Navy of the United States." By virtue
of this constitutional office he has supreme command over the land and naval
forces of the country and may order them to perform such military duties as,
in his opinion, are necessary or appropriate for the defense of the United
States. These powers exist in time of peace as well as in time of war.

. . . .

Thus the President's responsibility as Commander in Chief embraces the authority
to command and direct the armed forces in their immediate movements and operations
designed to protect the security and effectuate the defense of the United
States. . . . [T]his authority undoubtedly includes the power to dispose of
troops and equipment in such manner and on such duties as best to promote
the safety of the country.

Training of British Flying Students in the United States, 40 Op.
Att'y Gen. 58, 61-62 (1941).(11) Other Attorneys
General have defended similar accounts of the President constitutional powers
and duties, particularly in times of unforeseen emergencies.

Attorney General William P. Barr, quoting the opinion of Attorney General
Jackson just cited, advised the President in 1992 that "[y]ou have authority
to commit troops overseas without specific prior Congressional approval 'on
missions of good will or rescue, or for the purpose of protecting American
lives or property or American interests.'" Authority to Use United States
Military Forces in Somalia, 16 Op. O.L.C. at 6 (citation omitted).

Attorney General (later Justice) Frank Murphy, though declining to define
precisely the scope of the President's independent authority to act in emergencies
or states of war, stated that:

the Executive has powers not enumerated in the statutes - powers derived
not from statutory grants but from the Constitution. It is universally recognized
that the constitutional duties of the Executive carry with them the constitutional
powers necessary for their proper performance. These constitutional powers
have never been specifically defined, and in fact cannot be, since their extent
and limitations are largely dependent upon conditions and circumstances. .
. . The right to take specific action might not exist under one state of facts,
while under another it might be the absolute duty of the Executive to take
such action.

Request of the Senate for an Opinion as to the Powers of the President
"In Emergency or State of War," 39 Op. Att'y Gen. 343, 347-48 (1939).

Attorney General Thomas Gregory opined in 1914 that "[i]n the preservation
of the safety and integrity of the United States and the protection of its
responsibilities and obligations as a sovereignty, [the President's] powers
are broad." Censorship of Radio Stations, 30 Op. Att'y Gen. 291,
292 (1914).

Finally, in 1898, Acting Attorney General John K. Richards wrote:

The preservation of our territorial integrity and the protection of our foreign
interests is intrusted, in the first instance, to the President. . . . In
the protection of these fundamental rights, which are based upon the Constitution
and grow out of the jurisdiction of this nation over its own territory and
its international rights and obligations as a distinct sovereignty, the President
is not limited to the enforcement of specific acts of Congress. [The President]
must preserve, protect, and defend those fundamental rights which flow from
the Constitution itself and belong to the sovereignty it created.

Foreign Cables, 22 Op. Att'y Gen. 13, 25-26 (1898). Acting Attorney
General Richards cited, among other judicial decisions, Cunningham v.
Neagle, 135 U.S. 1, 64 (1890), in which the Supreme Court stated that
the President's power to enforce the laws of the United States "include[s]
the rights, duties and obligations growing out of the constitution itself,
our international relations, and all the protection implied by the nature
of the government under the constitution."

Opinions of the Office of Legal Counsel. Our Office has taken the
position in recent Administrations, including those of Presidents Clinton,
Bush, Reagan, Carter, and Nixon, that the President may unilaterally deploy
military force in order to protect the national security and interests of
the United States.

In 1995, we opined that the President "acting without specific statutory
authorization, lawfully may introduce United States ground troops into Bosnia
and Herzegovina . . . to help the North Atlantic Treaty Organization . . .
ensure compliance with the recently negotiated peace agreement." Proposed
Deployment of United States Armed Forces in Bosnia and Herzegovina, 19
Op. O.L.C. 327, 327 (1995) (the "Bosnia Opinion"). We interpreted the WPR
to "lend[] support to the . . . conclusion that the President has authority,
without specific statutory authorization, to introduce troops into hostilities
in a substantial range of circumstances." Id. at 335.

In Deployment of United States Armed Forces into Haiti, 18 Op.
O.L.C. 173 (1994), we advised that the President had the authority unilaterally
to deploy some 20,000 troops into Haiti. We relied in part on the structure
of the WPR, which we argued "makes sense only if the President may introduce
troops into hostilities or potential hostilities without prior authorization
by the Congress." Id. at 175-76. We further argued that "in establishing
and funding a military force that is capable of being projected anywhere around
the globe, Congress has given the President, as Commander in Chief, considerable
discretion in deciding how that force is to be deployed." Id. at
177. We also cited and relied upon the past practice of the executive branch
in undertaking unilateral military interventions:

In 1940, after the fall of Denmark to Germany, President Franklin Roosevelt
ordered United States troops to occupy Greenland, a Danish possession in the
North Atlantic of vital strategic interest to the United States. . . . Congress
was not consulted or even directly informed. . . . Later, in 1941, the President
ordered United States troops to occupy Iceland, an independent nation, pursuant
to an agreement between himself and the Prime Minister of Iceland. The President
relied upon his authority as Commander in Chief, and notified Congress only
after the event. . . . More recently, in 1989, at the request of President
Corazon Aquino, President Bush authorized military assistance to the Philippine
government to suppress a coup attempt.

Id. at 178.

In Authority to Use United States Military Forces in Somalia, 16
Op. O.L.C. at 8, our Office advised that the President had the constitutional
authority to deploy United States Armed Forces into Somalia in order to assist
the United Nations in ensuring the safe delivery of relief to distressed areas
of that country. We stated that "the President's role under our Constitution
as Commander in Chief and Chief Executive vests him with the constitutional
authority to order United States troops abroad to further national interests
such as protecting the lives of Americans overseas." Id. at 8. Citing
past practice (further discussed below), we pointed out that

[f]rom the instructions of President Jefferson's Administration to Commodore
Richard Dale in 1801 to 'chastise' Algiers and Tripoli if they continued to
attack American shipping, to the present, Presidents have taken military initiatives
abroad on the basis of their constitutional authority. . . . Against the background
of this repeated past practice under many Presidents, this Department and
this Office have concluded that the President has the power to commit United
States troops abroad for the purpose of protecting important national interests.

Id. at 9 (citations omitted).

In Overview of the War Powers Resolution, 8 Op. O.L.C. 271, 275
(1984), we noted that "[t]he President's authority to deploy armed forces
has been exercised in a broad range of circumstances [in] our history."

In Presidential Power to Use the Armed Forces Abroad Without Statutory
Authorization, 4A Op. O.L.C. 185, 187 (1980), we stated that

[o]ur history is replete with instances of presidential uses of military
force abroad in the absence of prior congressional approval. This pattern
of presidential initiative and congressional acquiescence may be said to reflect
the implicit advantage held by the executive over the legislature under our
constitutional scheme in situations calling for immediate action. Thus, constitutional
practice over two centuries, supported by the nature of the functions exercised
and by the few legal benchmarks that exist, evidences the existence of broad
constitutional power.

In light of that understanding, we advised that the President had independent
constitutional authority unilaterally to order "(1) deployment abroad at some
risk of engagement - for example, the current presence of the fleet in the
Persian Gulf region; (2) a military expedition to rescue the hostages or to
retaliate against Iran if the hostages are harmed; (3) an attempt to repel
an assault that threatens our vital interests in that region." Id.
at 185-86. See also Presidential Powers Relating to the Situation in Iran,
4A Op. O.L.C. 115, 121 (1979) ("It is well established that the President
has the constitutional power as Chief Executive and Commander-in-Chief to
protect the lives and property of Americans abroad. This understanding is
reflected in judicial decisions. . . and recurring historic practice which goes back to the time of Jefferson.").

Finally, in the Rehnquist Memo at 8, we concluded that the President as
Commander in Chief had the authority "to commit military forces of the United
States to armed conflict . . . to protect the lives of American troops in
the field."

Judicial Construction. Judicial decisions since the beginning
of the Republic confirm the President's constitutional power and duty to repel
military action against the United States through the use of force, and to
take measures to deter the recurrence of an attack. As Justice Joseph Story
said long ago, "[i]t may be fit and proper for the government, in the exercise
of the high discretion confided to the executive, for great public purposes,
to act on a sudden emergency, or to prevent an irreparable mischief, by summary
measures, which are not found in the text of the laws." The Apollon,
22 U.S. (9 Wheat.) 362, 366-67 (1824). The Constitution entrusts the "power
[to] the executive branch of the government to preserve order and insure the
public safety in times of emergency, when other branches of the government
are unable to function, or their functioning would itself threaten the public
safety." Duncan v. Kahanamoku, 327 U.S. 304, 335 (1946) (Stone, C.J.,
concurring).

If the President is confronted with an unforeseen
attack on the territory and people of the United States, or other immediate,
dangerous threat to American interests and security, the courts have affirmed
that it is his constitutional responsibility to respond to that threat with
whatever means are necessary, including the use of military force abroad. See,
e.g., Prize Cases, 67 U.S. at 635 ("If a war be made by invasion
of a foreign nation, the President is not only authorized but bound to resist
force by force . . . without waiting for any special legislative authority.");
Kahanamoku, 327 U.S. at 336 (Stone, C.J., concurring) ("Executive has
broad discretion in determining when the public emergency is such as to give
rise to the necessity" for emergency measures); United States v. Smith,
27 F. Cas. 1192, 1230 (C.C.D.N.Y. 1806) (No. 16,342) (Paterson, Circuit Justice)
(regardless of statutory authorization, it is "the duty . . . of the executive
magistrate . . . to repel an invading foe") (12);
Mitchell v. Laird, 488 F.2d 611, 613 (D.C. Cir. 1973) ("there are some
types of war which without Congressional approval, the President may begin to
wage: for example, he may respond immediately without such approval to a belligerent
attack") (13); see also Campbell v. Clinton,
203 F.3d 19, 27 (D.C. Cir.) (Silberman, J. concurring) ("[T]he President has
independent authority to repel aggressive acts by third parties even without
specific statutory authorization."), cert. denied, 531 U.S. 815 (2000);id.
at 40 (Tatel, J., concurring) ("[T]he President,as Commander
in Chief, possesses emergency authority to use military force to defend the
nation from attack without obtaining prior congressional approval."); Story,
supra note 9, § 1485 ("[t]he command and application of the public
force . . . to maintain peace, and to resist foreign invasion" are executive
powers).

III.

The historical practice of all three branches confirms the lessons of the
constitutional text and structure. The normative role of historical practice
in constitutional law, and especially with regard to separation of powers,
is well settled. (14) Both the Supreme Court
and the political branches have often recognized that governmental practice
plays a highly significant role in establishing the contours of the constitutional
separation of powers: "a systematic, unbroken, executive practice, long pursued
to the knowledge of the Congress and never before questioned . . . may be
treated as a gloss on 'executive Power' vested in the President by § 1 of
Art. II." Youngstown Sheet & Tube Co., 343 U.S. at 610-11 (Frankfurter,
J., concurring). Indeed, as the Court has observed, the role of practice in
fixing the meaning of the separation of powers is implicit in the Constitution
itself: "'the Constitution . . . contemplates that practice will integrate
the dispersed powers into a workable government.'" Mistretta v. United
States, 488 U.S. 361, 381 (1989) (citation omitted). In addition, governmental
practice enjoys significant weight in constitutional analysis for practical
reasons, on "the basis of a wise and quieting rule that, in determining .
. . the existence of a power, weight shall be given to the usage itself -
even when the validity of the practice is the subject of investigation." United
States v. Midwest Oil Co., 236 U.S. 459, 473 (1915).

The role of practice is heightened in dealing with issues affecting foreign
affairs and national security, where "the Court has been particularly willing
to rely on the practical statesmanship of the political branches when considering
constitutional questions." Whether Uruguay Round Agreements Required Ratification
as a Treaty, 18 Op. O.L.C. 232, 234(1994). "The persistence
of these controversies (which trace back to the eighteenth century), and the
nearly complete absence of judicial decisions resolving them, underscore the
necessity of relying on congressional precedent to interpret the
relevant constitutional provisions." Id. at 236. Accordingly, we
give considerable weight to the practice of the political branches in trying
to determine the constitutional allocation of warmaking powers between them.

The historical record demonstrates that the power to initiate military hostilities,
particularly in response to the threat of an armed attack, rests exclusively
with the President. As the Supreme Court has observed, "[t]he United States
frequently employs Armed Forces outside this country - over 200 times in our
history - for the protection of American citizens or national security." United
States v. Verdugo-Urquidez, 494 U.S. 259, 273 (1990). On at least 125
such occasions, the President acted without prior express authorization from
Congress. See Bosnia Opinion, 19 Op. O.L.C. at 331. Such deployments,
based on the President's constitutional authority alone, have occurred since
the Administration of George Washington. See David P. Currie, The
Constitution in Congress: Substantive Issues in the First Congress, 1789-1791,
61 U. Chi. L. Rev. 775, 816 (1994) ("[B]oth Secretary [of War] Knox and [President]
Washington himself seemed to think that this [Commander in Chief] authority
extended to offensive operations taken in retaliation for Indian atrocities.")
(quoted in Bosnia Opinion, 19 Op. O.L.C. at 331 n.4. Perhaps the most significant
deployment without specific statutory authorization took place at the time
of the Korean War, when President Truman, without prior authorization from
Congress, deployed United States troops in a war that lasted for over three
years and caused over 142,000 American casualties. See Bosnia Opinion,
19 Op. O.L.C. at 331-32 n.5.

Recent deployments ordered solely on the basis of the President's constitutional
authority have also been extremely large, representing a substantial commitment
of the Nation's military personnel, diplomatic prestige, and financial resources.
On at least one occasion, such a unilateral deployment has constituted full-scale
war. On March 24, 1999, without any prior statutory authorization and in the
absence of an attack on the United States, President Clinton ordered hostilities
to be initiated against the Republic of Yugoslavia. The President informed
Congress that, in the initial wave of air strikes, "United States and NATO
forces have targeted the [Yugoslavian] government's integrated air defense
system, military and security police command and control elements, and military
and security police facilities and infrastructure. . . . I have taken these
actions pursuant to my constitutional authority to conduct U.S. foreign relations
and as Commander in Chief and Chief Executive." Letter to Congressional
leaders reporting on airstrikes against Serbian targets in the Federal Republic
of Yugoslavia (Serbia and Montenegro), 1 Pub. Papers of William Jefferson
Clinton 459, 459 (1999). Bombing attacks against targets in both Kosovo
and Serbia ended on June 10, 1999, seventy-nine days after the war began.
More than 30,000 United States military personnel participated in the operations;
some 800 U.S. aircraft flew more than 20,000 sorties; more than 23,000 bombs
and missiles were used. As part of the peace settlement, NATO deployed some
50,000 troops into Kosovo, 7,000 of them American. (15)
In a News Briefing on June 10, 1999, Secretary of Defense William S. Cohen
summarized the effects of the campaign by saying,

[t]hree months ago Yugoslavia was a heavily armed country with a significant
air defense system. We reduced that defense system threat by destroying over
80 percent of Yugoslavia's modern aircraft fighters and strategic suface-to-air
missiles. NATO destroyed a significant share of the infrastructure Yugoslavia
used to support[] its military with, we reduced his capacity to make ammunition
by two-thirds, and we eliminated all of its oil refining capacity and more
than 40 percent of its military fuel supplies, Most important, we severely
crippled the military forces in Kosovo by destroying more than 50 percent
of the artillery and more than one-third of the armored vehicles.
(16)

General Shelton of the Joint Chiefs of Staff reported that "about half of
[Yugoslavia's] defense industry has either been damaged or destroyed. . .
. [A]viation, 70 percent; armored vehicle production, 40 [percent]; petroleum
refineries, 100 percent down; explosive production, about 50 percent; and
65 percent of his ammunition. . . . For the most part Belgrade is a city that's
got about probably 70 percent without [electrical] power."
(17) A report by General Ryan, Air Force Chief of Staff, on June
8, 1999, stated that

Serbia's air force is essentially useless and its air defenses are dangerous
but ineffective. Military armament production is destroyed. Military supply
areas are under siege. Oil refinement has ceased and petroleum storage is
systematically being destroyed. Electricity is sporadic, at best. Major transportation
routes are cut. NATO aircraft are attacking with impunity throughout the country.
(18)

Estimates near the time placed the number of Yugoslav military casualties
at between five and ten thousand. (19) In
recent decades, no President has unilaterally deployed so much force abroad.

Other recent unilateral deployments have also been significant in military,
foreign policy, and financial terms. Several such deployments occurred in
the Balkans in the mid-1990s. (20) In December
1995, President Clinton ordered the deployment of 20,000 United States troops
to Bosnia to implement a peace settlement. In February 1994, sixty United
States warplanes conducted airstrikes against Yugoslav targets. In 1993, United
States warplanes were sent to enforce a no-fly zone over Bosnia; in the same
year, the President despatched United States troops to Macedonia as part of
a United Nations peacekeeping operation.

Major recent deployments have also taken place in Central America and in
the Persian Gulf. In 1994, President Clinton ordered some 20,000 United States
troops to be deployed into Haiti, again without prior statutory authorization
from Congress, in reliance solely upon his Article II authority. See Deployment
of United States Armed Forces into Haiti, supra. On August 8,
1990, in response to the Iraqi invasion of Kuwait and the consequent threat
to Saudi Arabia, President Bush ordered the deployment of substantial forces
into Saudi Arabia in Operation Desert Shield. The forces were equipped for
combat and included two squadrons of F-15 aircraft and a brigade of the 82d
Airborne Division; the deployment eventually grew to several hundred thousand.
The President informed Congress that he had taken these actions "pursuant
to my constitutional authority to conduct our foreign relations and as Commander
in Chief." Letter to Congressional Leaders, 2 Pub. Papers of
George Bush 1116 (1990). President Bush also deployed some 15,000 troops
into Panama in December, 1990, for the purpose (among others) of protecting
Americans living in Panama. See 2 Pub. Papers of George Bush
1722 (1989); see generallyAbraham D. Sofaer, The
Legality of the United States Action in Panama, 29 Colum. J. Transnat'l
L. 281 (1991).

Further, when Congress has in fact authorized deployments of troops in hostilities,
past Presidents have taken the position that such legislation, although welcome,
was not constitutionally necessary. For example, in signing Pub. L. No. 102-01,
105 Stat. 3 (1991), authorizing the use of military force in Operation Desert
Storm against Iraq, President Bush stated that "my request for congressional
support did not, and my signing this resolution does not, constitute any change
in the longstanding positions of the executive branch on either the President's
constitutional authority to use the Armed Forces to defend vital U.S. interests
or the constitutionality of the War Powers Resolution." Statement on Signing
the Resolution Authorizing the Use of Military Force Against Iraq, 1
Pub. Papers of George Bush 40 (1991). (21)Similarly, President John F. Kennedy stated on September 13, 1962, that
congressional authorization for a naval blockade of Cuba was unnecessary,
maintaining that "I have full authority now to take such action." Pub.
Papers of John F. Kennedy 674 (1962). And in a Report to the American
People on October 22, 1962, President Kennedy asserted that he had ordered
the blockade "under the authority entrusted to me by the Constitution as
endorsed by the resolution of the Congress." Id. at 807 (emphasis
added). (22) Thus, there is abundant precedent,
much of it from recent Administrations, for the deployment of military force
abroad, including the waging of war, on the basis of the President's sole
constitutional authority.

Several recent precedents stand out as particularly relevant to the situation
at hand, where the conflict is with terrorists. The first and most relevant
precedent is also the most recent: the military actions that President William
J. Clinton ordered on August 20, 1998, against terrorist sites in Afghanistan
and Sudan. The second is the strike on Iraqi Intelligence Headquarters that
President Clinton ordered on June 26, 1993. The third is President Ronald
Reagan's action on April 14, 1986, ordering United States armed forces to
attack selected targets at Tripoli and Benghazi, Libya.

(A) On August 20, 1998, President Clinton ordered the Armed Forces to strike
at terrorist-related facilities in Afghanistan and Sudan "because of the threat
they present to our national security." Remarks in Martha's Vineyard,
Massachusetts, on Military Action Against Terrorist Sites in Afghanistan and
Sudan, 2 Pub. Papers of William J. Clinton 1460 (1998). The President
stated that the purpose of the operation was "to strike at the network of
radical groups affiliated with and funded by Usama bin Ladin, perhaps the
preeminent organizer and financier of international terrorism in the world
today." Address to the Nation on Military Action Against Terrorist Sites
in Afghanistan and Sudan, 2 Pub. Papers of William J. Clinton 1460
(1998). The strike was ordered in retaliation for the bombings of United States
Embassies in Kenya and Tanzania, in which bin Laden's organization and groups
affiliated with it were believed to have played a key role and which had caused
the deaths of some 12 Americans and nearly 300 Kenyans and Tanzanians, and
in order to deter later terrorist attacks of a similar kind against United
States nationals and others. In his remarks at Martha's Vineyard, President
Clinton justified the operation as follows:

I ordered this action for four reasons: first, because we have convincing
evidence these groups played the key role in the Embassy bombings in Kenya
and Tanzania; second, because these groups have executed terrorist attacks
against Americans in the past; third, because we have compelling information
that they were planning additional terrorist attacks against our citizens
and others with the inevitable collateral casualties we saw so tragically
in Africa; and fourth, because they are seeking to acquire chemical weapons
and other dangerous weapons.

Id. In his Address to the Nation on the same day, the President
made clear that the strikes were aimed, not only at bin Laden's organization,
but at other terrorist groups thought to be affiliated with it, and that the
strikes were intended as retribution for other incidents caused by these groups,
and not merely the then-recent bombings of the two United States embassies.
Referring to the past acts of the interlinked terrorist groups, he stated:

Their mission is murder and their history is bloody. In recent years, they
killed American, Belgian, and Pakistani peacekeepers in Somalia. They plotted
to assassinate the President of Egypt and the Pope. They planned to bomb six
United States 747's over the Pacific. They bombed the Egyptian Embassy in
Pakistan. They gunned down German tourists in Egypt.

Id. at 1460-61.Furthermore, in explaining why military
action was necessary, the President noted that "law enforcement and diplomatic
tools" to combat terrorism had proved insufficient, and that "when our very
national security is challenged . . . we must take extraordinary steps to
protect the safety of our citizens." Id. at 1461. Finally, the President
made plain that the action of the two targeted countries in harboring terrorists
justified the use of military force on their territory: "The United States
does not take this action lightly. Afghanistan and Sudan have been warned
for years to stop harboring and supporting these terrorist groups. But countries
that persistently host terrorists have no right to be safe havens." Id.

The terrorist incidents of September 11, 2001, were surely far graver a
threat to the national security of the United States than the 1998 attacks
on our embassies (however appalling those events were). The President's power
to respond militarily to the later attacks must be correspondingly broader.
Nonetheless, President Clinton's action in 1998 illustrates some of the breadth
of the President's power to act in the present circumstances.

First, President Clinton justified the targeting of particular groups on
the basis of what he characterized as "convincing" evidence of their involvement
in the embassy attacks. While that is not a standard of proof appropriate
for a criminal trial, it is entirely appropriate for military and political
decisionmaking. Second, the President targeted not merely one particular group
or leader, but a network of affiliated groups. Moreover, he ordered the action,
not only because of particular attacks on United States embassies, but because
of a pattern of terrorist activity, aimed at both Americans and non-Americans,
that had unfolded over several years. Third, the President explained that
the military action was designed to deter future terrorist incidents,
not only to punish past ones. Fourth, the President specifically justified
military action on the territory of two foreign states because their governments
had "harbor[ed]" and "support[ed]" terrorist groups for years, despite warnings
from the United States.

(B) On June 26, 1993, President Clinton ordered a Tomahawk cruise missile
strike on Iraqi Intelligence Service (the "IIS") headquarters in Baghdad.
The IIS had planned an unsuccessful attempt to assassinate former President
Bush in Kuwait in April, 1993. Two United States Navy surface ships launched
a total of 23 missiles against the IIS center.

In a Letter to Congressional Leaders on the Strike on Iraqi Intelligence
Headquarters,1 Pub. Papers of William J. Clinton 940
(1993), the President referred to the failed assassination attempt and stated
that "[t]he evidence of the Government of Iraq's violence and terrorism demonstrates
that Iraq poses a continuing threat to United States nationals." He based
his authority to order a strike against the Iraqi government's intelligence
command center on "my constitutional authority with respect to the conduct
of foreign relations and as Commander in Chief," as well as on the Nation's
inherent right of self-defense. Id.

President Clinton's order was designed in part to deter and prevent future
terrorist attacks on the United States - and most particularly future assassination
attempts on former President Bush. Although the assassination attempt had
been frustrated by the arrest of sixteen suspects before any harm was done,
"nothing prevented Iraq from directing a second - possibly successful - attempt
on Bush's life. Thus, the possibility of another assassination plot was 'hanging
threateningly over [Bush's] head' and was therefore imminent. By attacking
the Iraqi Intelligence Service, the United States hoped to prevent and deter
future attempts to kill Bush." (23)

(C) On April 14, 1986, President Ronald Reagan, acting on his independent
authority, ordered United States armed forces to engage in military action
against the government of Colonel Gadhafi of Libya.
(24) Thirty-two American aircraft attacked selected targets at Tripoli
and Benghazi, Libya. Libyan officials reported thirty-seven people killed
and an undetermined number injured. More than sixty tons of ordnance were
used during the attack.

For some time Libya had supported terrorist groups and organizations and
indeed had itself ordered direct terrorist attacks on the United States.

Under Gaddafi, Libya has declared its support of 'national liberation movements'
and has allegedly financed and trained numerous terrorist groups and organizations,
including Palestinian radicals, Lebanese leftists, Columbia's M-19 guerrillas,
the Irish Republican Army, anti-Turkish Armenians, the Sandinistas in Nicaragua,
Muslim rebels in the Philippines, and left-wing extremists in Europe and Japan.
(25)

It had harbored a variety of terrorists, including Abu Nidal and the three
surviving members of the Black September group that had killed eleven Israeli
athletes at the 1972 Munich Olympic Games. (26)
Libya's attacks on the United States included the murder of two United States
diplomats in Khartoum (1973), the attempted assassination of Secretary of
State Kissinger (1973), the burning of the United States Embassy in Tripoli
(1979), the planned assassination of President Reagan, Secretary of State
Haig, Secretary of Defense Weinberger, and Ambassador to Italy Robb (1981),
and the hijacking of T.W.A. flight 847 (1985). (27)
Libya had also been linked to terrorist events close to the time of the April,
1986, airstrike in which Americans and other had lost their lives. In January,
1986, American intelligence tied Libya to the December 27, 1985, bombings
at the Rome and Vienna airports in which nineteen people, including 5 Americans,
had died, and one hundred and twelve persons had been injured.

The particular event that triggered the President's military action had
occurred on April 5, 1986, when a bomb exploded in the "Labelle," a Berlin
discotheque frequented by U.S. military personnel. The blast killed three
people (two Americans) and injured two hundred and thirty others (including
seventy-nine Americans). Intelligence reports indicated that the bombing was
planned and executed under the direct orders of the Government of Libya. The
United States Ambassador to the United Nations stated that there was "direct,
precise, and irrefutable evidence that Libya bears responsibility" for the
bombing of the discotheque; that the "Labelle" incident was "only the latest
in an ongoing pattern of attacks" by Libya against the United States and its
allies; and that the United States had made "repeated and protracted efforts
to deter Libya from its ongoing attacks," including "quiet diplomacy, public
condemnation, economic sanctions, and demonstrations of military force." U.N.
SCOR, 2674th mtg. at 16-17, U.N. Doc. S/PV.2674 (prov. ed. 1986).

Like the two unilateral Presidential actions discussed above, President
Reagan's decision to use armed force in response to a terrorist attack on
United States military personnel illustrates that the President has independent
constitutional authority to use such force in the present circumstances.

IV.

Our analysis to this point has surveyed the views and practice of the executive
and judicial branches. In two enactments, the War Powers Resolution and the
recent Joint Resolution, Congress has also addressed the scope of the President's
independent constitutional authority. We think these two statutes demonstrate
Congress's acceptance of the President's unilateral war powers in an emergency
situation like that created by the September 11 incidents.

Furthermore, the President can be said to be acting at the apogee of his
powers if he deploys military force in the present situation, for he is operating
both under his own Article II authority and with the legislative support of
Congress. Under the analysis outlined by Justice Jackson in Youngstown
Sheet & Tube Co., supra (and later followed and interpreted
by the Court in Dames & Moore, supra), the President's power
in this case would be "at its maximum," 343 U.S. at 635 (Jackson, J., concurring),
because the President would be acting pursuant to an express congressional
authorization. He would thus be clothed with "all [authority] that he possesses
in his own right plus all that Congress can delegate," id., in addition
to his own broad powers in foreign affairs under Article II of the Constitution.

The War Powers Resolution. Section 2(c) of the WPR, reads as follows:

The constitutional powers of the President as Commander-in-Chief to introduce
United States Armed Forces into hostilities, or into situations where imminent
involvement in hostilities is clearly indicated by the circumstances, are
exercised only pursuant to (1) a declaration of war, (2) specific statutory
authorization, or (3) a national emergency created by attack upon the
United States, its territories or possessions, or its armed forces.

50 U.S.C. § 1541(c) (emphasis added).

The executive branch consistently "has taken the position from the very
beginning that section 2(c) of the WPR does not constitute a legally binding
definition of Presidential authority to deploy our armed forces." Overview
of the War Powers Resolution, 8 Op. O.L.C. at 274.
(28) Moreover, as our Office has noted, "even the defenders of the
WPR concede that this declaration [in section 2(c)] - found in the 'Purpose
and Policy' section of the WPR - either is incomplete or is not meant to be
binding." Deployment of United States Armed Forces into Haiti, 18
Op. O.L.C. at 176; accord Bosnia Opinion, 19 Op. O.L.C. at 335 ("The
executive branch has traditionally taken the position that the President's
power to deploy armed forces into situations of actual or indicated hostilities
is not restricted to the three categories specifically marked out by the Resolution.");
Presidential Powers Relating to the Situation in Iran, 4A Op. O.L.C.
at 121 ("[T]he Resolution's policy statement is not a comprehensive or binding
formulation of the President's powers as Commander-in-Chief."). Nonetheless,
section 2(c)(3) correctly identifies one, but by no means the only,
Presidential authority to deploy military forces into hostilities.
(29) In the present circumstances, the statute signifies Congress's
recognition that the President's constitutional authority alone would enable
him to take military measures to combat the organizations or groups responsible
for the September 11 incidents, together with any governments that may have
harbored or supported them.

Further, Congress's support for the President's power suggests no limits
on the Executive's judgment whether to use military force in response to the
national emergency created by those incidents. Section 2(c)(3) leaves undisturbed
the President's constitutional authority to determine both when a "national
emergency" arising out of an "attack against the United States" exists, and
what types and levels of force are necessary or appropriate to respond to
that emergency. Because the statute itself supplies no definition of these
terms, their interpretation must depend on longstanding constitutional practices
and understandings. As we have shown in Parts I-III of this memorandum, constitutional
text, structure and practice demonstrate that the President is vested with
the plenary power to use military force, especially in the case of a direct
attack on the United States. Section 2(c)(3) recognizes the President's broad
authority and discretion in this area.

Given the President's constitutional powers to respond to national emergencies
caused by attacks on the United States, and given also that section 2(c)(3)
of the WPR does not attempt to define those powers, we think that that provision
must be construed simply as a recognition of, and support for, the President's
pre-existing constitutional authority. Moreover, as we read the WPR, action
taken by the President pursuant to the constitutional authority recognized
in section 2(c)(3) cannot be subject to the substantive requirements of the
WPR, particularly the interrelated reporting requirements in section 4 and
the "cut off" provisions of section 5, 50 U.S.C. §§ 1543-1544.
(30) Insofar as the Constitution vests the power in the President
to take military action in the emergency circumstances described by section
2(c)(3), we do not think it can be restricted by Congress through, e.g.,
a requirement that the President either obtain congressional authorization
for the action within a specific time frame, or else discontinue the action.
Were this not so, the President could find himself unable to respond to an
emergency that outlasted a statutory cut-off, merely because Congress had
failed, for whatever reason, to enact authorizing legislation within that
period.

To be sure, some interpreters of the WPR take a broader view of its scope.
But on any reasonable interpretation of that statute, it must reflect
an explicit understanding, shared by both the Executive and Congress, that
the President may take some military actions - including involvement
in hostilities - in response to emergencies caused by attacks on the United
States. Thus, while there might be room for disagreement about the scope and
duration of the President's emergency powers, there can be no reasonable doubt
as to their existence.

The Joint Resolution of September 14, 2001. Whatever view one may
take of the meaning of section 2(c)(3) of the WPR, we think it clear that
Congress, in enacting the "Joint Resolution [t]o authorize the use of United
States Armed Forces against those responsible for the recent attacks launched
against the United States," Pub. L. No. 107-40, 115 Stat. 224 (2001), has
confirmed that the President has broad constitutional authority to respond,
by military means or otherwise, to the incidents of September 11.

First, the findings in the Joint Resolution include an express statement
that "the President has authority under the Constitution to take action to
deter and prevent acts of international terrorism against the United States."
Id. This authority is in addition to the President's authority to
respond to past acts of terrorism. In including this statement, Congress
has provided its explicit agreement with the executive branch's consistent
position, as articulated in Parts I-III of this memorandum, that the President
has the plenary power to use force even before an attack upon the United States
actually occurs, against targets and using methods of his own choosing.

Second, Congress also found that there is a "threat to the national security
and foreign policy of the United States posed by the[] grave acts of violence"
on September 11, and that "such acts continue to pose an unusual and extraordinary
threat to the national security and foreign policy" of this country. Insofar
as "the President's independent power to act depends upon the gravity of the
situation confronting the nation," Youngstown Sheet & Tube Co.,
343 U.S. at 662 (Clark, J., concurring in judgment), these findings would
support any presidential determination that the September 11 attacks justified
the use of military force in response. Further, they would buttress any Presidential
determination that the nation is in a state of emergency caused by those attacks.
The Constitution confides in the President the authority, independent of any
statute, to determine when a "national emergency" caused by an attack on the
United States exists. (31) Nonetheless, congressional
concurrence is welcome in making clear that the branches agree on seriousness
of the terrorist threat currently facing the Nation and on the justifiability
of a military response.

Third, it should be noted here that the Joint Resolution is somewhat narrower
than the President's constitutional authority. The Joint Resolution's authorization
to use force is limited only to those individuals, groups, or states that
planned, authorized, committed, or aided the attacks, and those nations that
harbored them. It does not, therefore, reach other terrorist individuals,
groups, or states, which cannot be determined to have links to the September
11 attacks. Nonetheless, the President's broad constitutional power to use
military force to defend the Nation, recognized by the Joint Resolution itself,
would allow the President to take whatever actions he deems appropriate to
pre-empt or respond to terrorist threats from new quarters.

Conclusion

In light of the text, plan, and history of the Constitution, its interpretation
by both past Administrations and the courts, the longstanding practice of
the executive branch, and the express affirmation of the President's constitutional
authorities by Congress, we think it beyond question that the President has
the plenary constitutional power to take such military actions as he deems
necessary and appropriate to respond to the terrorist attacks upon the United
States on September 11, 2001. Force can be used both to retaliate for those
attacks, and to prevent and deter future assaults on the Nation. Military
actions need not be limited to those individuals, groups, or states that participated
in the attacks on the World Trade Center and the Pentagon: the Constitution
vests the President with the power to strike terrorist groups or organizations
that cannot be demonstrably linked to the September 11 incidents, but that,
nonetheless, pose a similar threat to the security of the United States and
the lives of its people, whether at home or overseas.
(32) In both the War Powers Resolution and the Joint Resolution,
Congress has recognized the President's authority to use force in circumstances
such as those created by the September 11 incidents. Neither statute, however,
can place any limits on the President's determinations as to any terrorist
threat, the amount of military force to be used in response, or the method,
timing, and nature of the response. These decisions, under our Constitution,
are for the President alone to make.

2. See also The Federalist No. 34, at 175 (Alexander Hamilton) (Federal
government is to possess "an indefinite power of providing for emergencies
as they might arise"); id. No. 41, at 224 (James Madison) ("Security
against foreign danger is one of the primitive objects of civil society. .
. . The powers requisite for attaining it must be effectually confided to
the foederal councils."). Many Supreme Court opinions echo Hamilton's argument
that the Constitution presupposes the indefinite and unpredictable nature
of the "the circumstances which may affect the public safety," and that the
federal government's powers are correspondingly broad. See, e.g., Dames
& Moore v. Regan, 453 U.S. 654, 662 (1981) (noting that the President
"exercis[es] the executive authority in a world that presents each day some
new challenge with which he must deal"); Hamilton v. Regents, 293
U.S. 245, 264 (1934) (federal government's war powers are "well-nigh limitless"
in extent); Stewart v. Kahn, 78 U.S. (11Wall.) 493, 506 (1870) ("The
measures to be taken in carrying on war . . . are not defined [in the Constitution].
The decision of all such questions rests wholly in the discretion of those
to whom the substantial powers involved are confided by the Constitution.");
Miller v. United States, 78 U.S. (11 Wall.) 268, 305 (1870) ("The
Constitution confers upon Congress expressly power to declare war, grant letters
of marque and reprisal, and make rules respecting captures on land and water.
Upon the exercise of these powers no restrictions areimposed.
Of course the power to declare war involves the power to prosecute it by all
means and in any manner in which war may be legitimately prosecuted.").

3. See Johnson v. Eisentrager, 339 U.S. 763, 789 (1950) (President has
authority to deploy United States armed forces "abroad or to any particular
region"); Fleming v. Page, 50 U.S. (9 How.) 603, 615 (1850) ("As
commander-in-chief, [the President] is authorized to direct the movements
of the naval and military forces placed by law at his command, and to employ
them in the manner he may deem most effectual"); Loving v. United States,
517 U.S. 748, 776 (1996) (Scalia, J., concurring in part and concurring in
judgment) (The "inherent powers" of the Commander in Chief "are clearly extensive.");
Maul v. United States, 274 U.S. 501, 515-16 (1927) (Brandeis &
Holmes, JJ., concurring) (President "may direct any revenue cutter to cruise
in any waters in order to perform any duty of the service"); Massachusetts
v. Laird, 451 F.2d 26, 32 (1st Cir. 1971) (the President has "power as
Commander-in-Chief to station forces abroad"); Authority to Use United
States Military Forces in Somalia, 16 Op. O.L.C. 6 (1992).

4. See John C. Yoo, The Continuation of Politics by Other Means:
The Original Understanding of War Powers, 84 Cal. L. Rev. 167, 196-241
(1996).

5. See id. ("He must determine what degree of force the crisis demands.");
see also Eisentrager, 339 U.S. at 789 ("Certainly it is not the function
of the Judiciary to entertain private litigation - even by a citizen - which
challenges the legality, the wisdom, or the propriety of the Commander-in-Chief
in sending our armed forces abroad or to any particular region."); Chicago
& Southern Air Lines v. Waterman Steamship Corp., 333 U.S. 103, 111
(1948) ("The President, both as Commander-in-Chief and as the Nation's organ
for foreign affairs, has available intelligence services whose reports are
not and ought not to be published to the world. It would be intolerable that
courts, without the relevant information, should review and perhaps nullify
actions of the Executive taken on information properly held secret."); Ramirez
de Arellano v. Weinberger, 745 F.2d 1500, 1561 (D.C. Cir. 1984) (Scalia,
J., dissenting), vacated by 471 U.S. 1113 (1985); Ex parte Vallandigham,
28 F.Cas. 874, 922 (C.C.S.D. Ohio 1863) (No. 16,816) (in acting "under this
power where there is no express legislative declaration, the president is
guided solely by his own judgment and discretion"); Hefleblower v. United
States, 21 Ct. Cl. 228, 238 (Ct. Cl. 1886) ("The responsibility of declaring
what portions of the country were in insurrection and of declaring when the
insurrection came to an end was accorded to the President; when he declared
a portion of the country to be in insurrection the judiciary cannot try the
issue and find the territory national; conversely, when the President declared
the insurrection at an end in any portion of the country, the judiciary cannot
try the issue and find the territory hostile."); cf. United States v.
Chemical Found., Inc., 272 U.S. 1, 12 (1926) ("It was peculiarly within
the province of the Commander-in-Chief to know the facts and to determine
what disposition should be made of enemy properties in order effectively to
carry on the war.")

6. See, e.g., Louis Fisher, Presidential War Power 185-206
(1995); John Hart Ely, War and Responsibility: Constitutional Lessons
of Vietnam and Its Aftermath 3-5 (1993); Michael J. Glennon, Constitutional
Diplomacy 80-84 (1990); Louis Henkin, Constitutionalism, Democracy,
and Foreign Affairs 109 (1990); Harold Hongju Koh, The National Security
Constitution: Sharing Power After the Iran-Contra Affair 158-61 (1990);
Francis D. Wormuth & Edwin B. Firmage, To Chain the Dog of War: The
War Power of Congress in History and Law (2d ed. 1989).

7.
A subsequent version made clear "that the governor and commander-in-chief
shall have no power to commence war, or conclude peace, or enter into any
final treaty" without legislative approval. S.C. Const. art. XXXIII (1778),
reprinted in 6 The Federal and State Constitutions 3255
(Francis Newton Thorpe ed., 1909).

8.
Of the eight major wars fought by Great Britain prior to the ratification
of the Constitution, war was declared only once before the start of hostilities.
See Yoo, supra note 4, at 214-15. See also W.
Taylor Reveley, III, War Powers of the President and Congress: Who Holds
the Arrows and Olive Branch? 55 (1981) ("[U]ndeclared war was the norm
in eighteenth-century European practice, a reality brought home to Americans
when Britain's Seven Years' War with France began on this continent." ); William
Michael Treanor, Fame, The Founding, and The Power to Declare War,
82 Cornell L. Rev. 695, 709 (1997).

9.
James Iredell (later an Associate Justice of the Supreme Court) argued in
the North Carolina Ratifying Convention that "[f]rom the nature of the thing,
the command of armies ought to be delegated to one person only. The secrecy,
despatch, and decision, which are necessary in military operations, can only
be expected from one person." Debate in the North Carolina Ratifying Convention,
in 4 Jonathan Elliott, The Debates in the Several State Conventions
on the Adoption of the Federal Constitution as Recommended by the General
Convention at Philadelphia in 1787, at 107 (2d ed. 1987). See also
3 Joseph Story, Commentaries on the Constitution of the United States
§ 1485 (1833) (in military matters, "[u]nity of plan, promptitude, activity,
and decision, are indispensable to success; and these can scarcely exist,
except when single magistrate is entrusted exclusively with the power").

10.
Thus, Article II's enumeration of the Treaty and Appointments Clauses only
dilutes the unitary nature of the executive branch in regard to the exercise
of those powers, rather than transforming them into quasi-legislative functions.
See Constitutionality of Proposed Conditions to Senate Consent to the Interim
Convention on Conservation of North Pacific Fur Seals, 10 Op. O.L.C.
12, 17 (1986) ("Nothing in the text of the Constitution or the deliberations
of the Framers suggests that the Senate's advice and consent role in the treaty-making
process was intended to alter the fundamental constitutional balance between
legislative authority and executive authority.").

11.
At the time Attorney General Jackson delivered his opinion, the United States
was a neutral, and thus his conclusions about the President's powers did not
rest on any special considerations that might apply in time of war. Although
he stated that he was "inclined to the opinion"that a statute
(the Lend-Lease Act) authorized the decision under review, Jackson expressly
based his conclusion on the President's constitutional authority. Id.
at 61.

12. Justice
Paterson went on to remark that in those circumstances "it would I apprehend,
be not only lawful for the president to resist such invasion, but also to
carry hostilities into the enemy's own country." Id. at 1230.

13.
The court further observed that "in a grave emergency [the President] may,
without Congressional approval, take the initiative to wage war. . . . In
such unusual situations necessity confers the requisite authority upon the
President. Any other construction of the Constitution would make it self-destructive."
Id. at 613-14. Accord Massachusetts v. Laird, 451 F.2d at 31
("[t]he executive may without Congressional participation repel attack").

14. As
the Supreme Court has noted, "the decisions of the Court in th[e] area [of
foreign affairs] have been rare, episodic, and afford little precedential
value for subsequent cases." Dames & Moore, 453 U.S. at 661.
In particular, the difficulty the courts experience in addressing "the broad
range of vitally important day-to-day questions regularly decided by Congress
or the Executive" with respect to foreign affairs and national security makes
the judiciary "acutely aware of the necessity to rest [judicial] decision[s]
on the narrowest possible ground capable of deciding the case." Id.
at 660-61. Historical practice and the ongoing tradition of executive branch
constitutional interpretation therefore play an especially important role
in this area.

21.
Further, in a press conference on January 9, 1991, President Bush was asked
if he believed that he needed congressional authorization in order to begin
offensive operations against Iraq. He answered, "I don't think I need it.
I think Secretary Cheney expressed it very well the other day. There are different
opinions on either side of this question, but Saddam Hussein should be under
no question on this: I feel that I have the authority to fully implement the
United Nations resolutions." The President's News Conference on the Persian
Gulf Crisis, 1 Pub. Papers of George Bush 17, 20 (1991).

22.
An unsigned, unaddressed opinion in this Office's files, entitled Blockade
of Cuba (Oct. 19, 1962), states that "the President, in the exercise
of his constitutional power as Commander-in-Chief, can order a blockade without
prior Congressional sanction and without a declaration of war by Congress."
Id. at 9. Thus, the writers of the memorandum (presumably, either
this Office or the State Department Legal Adviser's Office) determined that
no Congressional authorization either existed or was necessary for the blockade
ordered by President Kennedy.

23.
Robert F. Teplitz, Taking Assassination Attempts Seriously: Did the United
States Violate International Law in Forcefully Responding to the Iraqi Plot
to Kill George Bush?, 28 Cornell Int'l L. J. 569, 609 (1995) (citation
omitted).

24. See generally Wallace F. Warriner, U.S.M.C., The Unilateral Use
of Coercion Under International Law: A Legal Analysis of the United States
Raid on Libya on April 14, 1986, 37 Naval L. Rev. 49 (1988); Teplitz,
supra n.23, at 583-86.

28.
Thus, the State Department took the view, in a letter of November 30, 1974,
that section 2(c) was a "declaratory statement of policy." Further, in 1975,
the Legal Adviser to the State Department listed six (non-exclusive) situations,
not enumerated in section 2(c), in which the President had independent constitutional
authority to deploy troops without either a declaration of war or specific
statutory authorization. Seeid. at 274-75.

29.
We note that section 2(c) cannot itself qualify as a statutory authorization
to act in national emergencies. It is rather a congressional acknowledgment
of the President's nonstatutory, Article II-based powers. Section
8(d)(2) of the WPR, 50 U.S.C. § 1547, specifically provides that nothing in
the WPR "shall be construed as granting any authority to the President . .
. which authority he would not have had in the absence of this [joint resolution]."

30. True,
the reporting requirement in section 4(a)(1) purports to apply to any case
in which U.S. armed forces are introduced into hostilities "[i]n the absence
of a declaration of war." 50 U.S.C. § 1543(a)(1). Further, the "cut off" provisions
of section 5 are triggered by the report required by section 4(a)(1). Thus,
the language of the WPR indicates an intent to reach action taken by the President
pursuant to the authority recognized in section 2(c)(3), if no declaration
of war has been issued. We think, however, that it would be beyond Congress's
power to regulate the President's emergency authority in the manner prescribed
by sections 4(a)(1) and 5.

31. See
Prize Cases, 67 U.S. at 670 (whether a state of belligerency justifying
a blockade exists is to be decided by the President); see alsoSterling
v. Constantin, 287 U.S. 378, 399 (1932) ("By virtue of his duty to 'cause
the laws to be faithfully executed', the Executive is appropriately vested
with the discretion to determine whether an exigency requiring military aid
for that purpose has arisen."); Moyer v. Peabody, 212 U.S. 78, 83
(1909) ("[T]he governor's declaration that a state of insurrection existed
is conclusive of that fact."); Campbell, 203 F.3d at 26-27 (Silberman,
J., concurring) (The Court in the Prize Cases "made clear that it
would not dispute the President on measures necessary to repel foreign aggression");
cf. Martin v. Mott, 25 U.S. (12 Wheat.) 19, 30 (1827) (President had
unreviewable discretion to determine when "emergency" existed under statute
enabling him to call up militia).

32.
We of course understand that terrorist organizations and their state sponsors
operate by secrecy and concealment, and that it is correspondingly difficult
to establish, by the standards of criminal law or even lower legal standards,
that particular individuals or groups have been or may be implicated in attacks
on the United States. Moreover, even when evidence sufficient to establish
involvement is available to the President, it may be impossible for
him to disclose that evidence without compromising classified methods and
sources, and so damaging the security of the United States. See, e.g.,
Chicago & Southern Air Lines, Inc, 333 U.S. at 111 ("The President
. . . has available intelligence services whose reports are not and ought
not to be published to the world."); see also Ruth Wedgwood, Responding
to Terrorism: The Strikes Against Bin Laden, 24 Yale J. Int'l L. 559,
568-74 (1999) (analyzing difficulties of establishing and publicizing evidence
of causation of terrorist incidents). But we do not think that the difficulty
or impossibility of establishing proof to a criminal law standard (or of making
evidence public) bars the President from taking such military measures as,
in his best judgment, he thinks necessary or appropriate to defend the United
States from terrorist attacks. In the exercise of his plenary power to use
military force, the President's decisions are for him alone and are unreviewable.